The present invention relates to a shift device, and more particularly, to a shift device for a toothed change transmission of a motor vehicle, and, more particularly, to a device comprising a manual-shift lever, a shift finger operatively connected with the manual shift lever such that actuation of the manual-shift lever displaces the shift finger both in a selection plane containing a geometrical main axis for a housing part and in the shift planes of the housing part lying transversely to the selection plane, and, with respect of the main axis, a pressure pin and a reaction sleeve.
In a known shift device of the type described in U.S. Pat. No. 3,164,030 (see, in particular, FIG. 4), the shift finger and the pressure pin are fixed relative to one another in terms of motion. As a result, the pressure-point spring, via the inclined face of the reaction sleeve and the reaction balls at the same time supported centripetally on the narrow pin portion, generates a constant frictional resistance on the manual-shift lever when the shift finger is actuated in the region of the selection plane limited by the first and the second shift plane. This device also requires a special return spring which is arranged concentrically on the wide pin portion and supported axially between the reaction sleeve, and an abutment of the wide pin portion to return the pressure pin out of the position in the region of the first shift plane.
An object of the present invention is to prevent in a shift device of the known type the occurrence of a frictional resistance exerted on the manual-shift lever by the reaction balls when the manual-shift lever is not actuated in order to select the third shift slot, i.e. in order to displace the shift finger into the third selection plane.
The foregoing object has been achieved in an advantageous way by arranging the shift finger and the pressure pin movably relative to one another in the directions of the main axis. An abutment sleeve is operatively arranged between the abutment and the associated spring end of the pressure-point spring and is arranged displaceably in the directions of the main axis both relative to the housing part and relative to the pressure pin. The abutment sleeve has a first axial stop in bearing contact on the abutment when the shift finger is located in the second shift plane and a second axial stop. The pressure pin has a corresponding axial stop. The two axial stops are in mutual bearing contact when the shift finger is in a first region of the selection plane limited by the first and the third shift plane. The shift finger and the abutment sleeve each have a cam, in mutual engagement when the shift finger is located in a second region of the selection plane limited by the second and by the third shift plane.
In the shift device according to the present invention, the pressure pin remains in a position of readiness relative to the housing part, fixed by the inclined faces and the radial guide face of the housing part, when the shift finger is located in the region of the selection plane limited by the first and the second shift plane. Thus, a frictional resistance cannot be generated by the reaction balls when the manual-shift lever is being actuated. A specific stop position for the abutment sleeve cooperating with the shift finger is provided when the shift finger is located in the third shift plane.
The present invention also provides for the return of the pressure pin out of the position in the region of the third shift plane into the position of readiness in the region of the first shift plane by using only the switching spring of a reversing-light switch arranged coaxially to the main axis and actuatable, i.e. switched on, by the pressure pin, instead of the special return spring required in aforementioned U.S. Pat. No. 3,164,030.
Thus, even though in the known shift device, the return spring, like the pressure-point spring, generates a constant frictional resistance on the manual-shift lever via the inclined face of the reaction sleeve and the reaction balls supported centripetally on the narrow pin portion, when the shift finger is actuated in the region of the selection plane limited by the first and the second shift plane, the present invention also prevents the occurrence of a frictional resistance exerted on the manual-shift lever by the reaction balls, when the manual-shift lever is not actuated in order to select the third shift slot, i.e. in order to displace the shift finger into the third selection plane, because the switching spring used as a return spring is, in principle, ineffective relative to the manual-shift lever in the respective region of the selection plane.
Should the spring force off the switching spring of the reversing-light switch be insufficient for the return of the pressure pin in the shift device according to the invention, however, a return spring can be provided either alone or in addition to the aforementioned switching spring.
Consequently, the present,invention also prevents the occurrence of a frictional resistance which can be exerted on the manual-shift lever by the reaction balls, when the manual-shift lever is not actuated in order to select the third shift slot (i.e. in order to displace the shift finger into the third selection plane) because the reaction balls remain uninfluenced by the return spring.